Blow-out chamber with insulating grids



July 24, 1934.

A. cLERc BLOW-OUT CHAMBER WITH INSULATING GRIDS Filed NOV. 24, .1933

Patented July 24, 1934 UNITED STATES 1,967,989 BLOW-OUT 011mm wrrn msomrmo cams Andr Clerc, Villeurbanne, France, assignor to Ateliers de Constructions Electriques de Belle.

Paris, France Application November 24. 1933, Serial No. 699,585

a In

9 Claims.

In electric circuit-breakers utilizing a compressed fluid for the "extinction of the arc, the arc is subjected to a blast of fluid within arc chambers or blowout chimneys.

Insome of these circuit-breakers a portion of the arc is developed approximately in the axis of the chamber or chimney in which'the blow out blast acts. The blowout effect is most intense in the centre of the chimney and particularly so when the blow out fluid is directed along this axis, and this is the case in most circuitbreakers. The blow out efiect is however less eflicient in the peripheral zones of the chimney and consequently eddies of fluid ionized by the are are formed in these zones. These eddies may provoke the restriking of the arc, and thisis particularly frequentafter the introduction of the resistances which are provided in some of these breakers.

The object of the present invention is to obviate these disadvantages. It consists in providing the interior of the chamber in which the arc is developed with at least one grid of insulating material in the'centre of which is provided a large channel for the passage of the arc.

The annexed drawing shows in section two embodiments of the invention. In thefollowing description of these two embodiments as well as in the claims the term insulating fluid is used to designate all gases and all liquids capable of being utilized for the extinction of the arc.

The circuit-breaker shown in Fig. 1 comprises a fixed contact 1 and amovable contact 2. The contact 1 is provided with an arcing contact 1' and the movable contact with an arcing contact 2. This latter is flxed to a pipe 3 through which is admitted the blow out fluid the direction of which is indicated by arrows. The movable contact 2 and is in electrical communication with this latter through a sliding contact 4. The contacts and arcing contacts are disposed on the interior of the converging nozzle 5 situated at the extremity of the pipe 3. This nozzle communicates with the divergent base 6 of the chim ney '7. In the interior of the chimney 7- two auxiliary electrodes 8 mounted on insulated conductors are in electrical contact with the movable contact through resistances 9 and the extreinity electrode 10 is directly connected to the fixed contact. All these electrodes as well as the arcing contact 2' are disposed along the common axis of the nozzle 5 and of the chimney '7. This latter near its outlet is provided with a flame baflle l1.

In the horizontal plane of the lower electrode 8 is disposed concentrically around this latter a grid 13 constituted by a thick plate of nonconducting material. This grid is provided with a plurality of channels 14. In the centre of this Germany November 25, 1932 rid and in the axis of the blow out chamber anv opening 12 is provided. The grid is thus annular and the section of the central channel is preferably smaller than that of the blow out blast at the point where it penetrates into the channel 12. The channel 12 may be of any shape whatsoever, cylindrical orotherwise. It is preferably conical such that its section diminishes in the direction of the blowout blast. In such a case, the narrowest part of the cone will have a smaller section than that of the blow out blast at the point where this latter penetrates into the cone.

The operation of the circuit breaker is as follows: The are developed on the opening of the contacts 1 and 2 is transferred through the influence of the blow out blast onto the members 10, 8, 8 and 2' and thus flnds itself disposed in a straight line in the centre of blast the envelope of which is indicated at 5' on the drawing. The fluid ionized by the arc-is dispelled towards the periphery of the chamber. Supposing the nonexistence of the grid 13, the ionized fluid will fill the space occupied by this grid and comprised between the wall of the chamber 7 and the external surface or the blow out blast. Under these circumstances, and after insertion of the lower resistance 9 into the circuit followed by the extinction of the are 2' 8, the restriking of an arc could be feared which would pass from the lower electrode 8 to the electrode 2 through the ionized fluid eddies circulating in the zone normally occupied by the grid. Thus the presence of the grid made of insulating material, at a point where, in its absence, there would exist conducting gases favoring the restriking of such an arc, effectively prevents the said restriking; Further, the internally convergent surface of the central channel 12 of this grid constricts the blow out blast in this particularly critical zone of the circuit breaker, and as a consequence of this effect the arc in this particular zone is more strongly deionized by the blast.

0n the other hand, the grid 13 accelerates upwardly the flow of ionized gases which are projected in the peripheric portion of the chamber are formed eddies which have a weak tendency only to flow upwardly.

The object of the channels 14 in the grid is to create in the lower peripheric portion of the chamber 7, comprised between said grid and its base 6, a slight increase in the pressure in the ionized fluid. This pressure increase attenuates the circulation of the eddies in this space and accelerates the flow of the ionized fluid contained therein towards the peripheric portion of the upper part of the chamber 7 above the grid. Further, by their passage between the insulating walls of the channels 14 these gases are deionized.

The grid 13 will preferably be made of wood.

7. Since herein the blowing is inefficient, there In certain embodiments of the invention, insulating grids may be disposed around each electrode situated in the central axis of the chimney. Finally, similar grids may be disposed around portions of the are situated between two successive electrodes, as for example between the two electrodes 8 or between'the electrodes 8 and 10; in all such cases their position would be parallel to that of the grid 13 shown in Fig. 1.

The best effect is obtained when, as shown in Fig. 1, the wall of the central channel, of the grid coincides approximately with the periphery of the blow out blast.

Instead of being constituted by a perforated insulating plate, the channels for the passage and for the deionization of the ionized fluid may be constituted in any other manner whatsoever.

Finally in Fig. 2 is shown an embodiment of the invention applied to a circuit-breaker in which the flxed contact 1 is hollow and funnel shaped, its orifice being closed by the movable contact 2 when in closed position. A portion of the are developed between the two contacts when the contact 2 is displaced in the direction of the arrow 16 is'drawn into the chamber '7 along the axis of this latter. In accordance with the invention the interior of this chamber is provided with a grid 13 having channels 14 as well as a large central channel 12 converging in the direction of the blast indicatedby the arrows without references. The are traverses the grid through the channel 12.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In an electric circuit-breaker,- relatively movable contacts, a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality of peripheral channels and with a large central channel, means for disposing part'of said are approximately .in the axis of said central chan nel, and means for projecting an insulating fluid around said are in a direction parallel to said axis.

2. In an electric circuit-breaker, relatively movable contacts, a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality of peripheral channels and with a large central channel, means for disposing said are approximately in the axis of said central channel and for directing a blast of insulating fluid through said central channel, the section of said blast at the point where it penetrates into said central channel being larger than the smallest section of said channel.

3. In an electric circuit-breaker, relatively mobile contacts,.a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality-of peripheral channels and with a large central channel, means for disposing said are approximately in the axis of said central channel and for directing a blast of insulating fluid through said central channel, the axes of all the chan- 1,oe7,9eo

-nels in said grid being parallel to the direction of said blast.

4. In an electric circuit-breaker, relatively movable contacts, a chamber in which a portion at least of the arc is developed, means for directing a blast of insulating fluid against said contacts and into said chamber, in the interior .of said chamber an auxiliary electrode connected to one of said contacts through a resistance, and a grid of insulating material disposed around said auxiliary electrode.

5. In an electric circuit-breaker, relatively movable contacts, a chamber in which a portion at least of the arc is developed, means for directing a blast of insulating fluid against said contacts and into said chamber, in the interior of said chamber an extremity electrode electrically connected tov one of said contacts, and a grid of insulating material disposed around said extremity electrode.

6. In an electric circuit-breaker, relatively movable contacts, a chamber in which a portion at least of the arc is developed, means for directing a blast of insulating fluid against said contacts and into said chamber, in the interior of said chamber a plurality of auxiliary electrodes connected to one of said contacts through a resistance, and a grid of insulating material disposed between'two of the said auxiliaryelec trodes.

"7. In an electric circuit-breaker, relatively mobile contacts, a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality of peripheral channels and with a large central cylindrical'channel, means for disposing said are approximately in the axis of said central channel and for directing a blast of insulating fluid through said central channel, the section of said fluid blast at the point where it penetrates into said central channel being larger than the section of said central channel.

8. In an electric circuit-breaker, relatively mobile contacts, a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality of peripheral channels and with a large central conical channel, means for disposing said are approximately in the axis of said central channel and 'for directing a blast of insulating fluid through said central channel, the section of said fluid blast at the point where it penetrates into said central channel being larger than the smallest section of said central channel.

9. In an electric circuit-breaker, relatively movable contacts, a chamber in which a portion at least of the arc is developed, at least one grid of insulating material in said chamber, said grid forming an annular ring with a plurality of peripheral channels and with a large central channel, means for disposing said are approximately in the axis of said central channel and for directing a blast of insulating fluid through said central channel, said central channel being concentric with the blow out blast and the section of said fluid blast at the point where it penetrates into said central channel being larger than the smallest section of said central channel.

ANDRE CLERC. 

